Enzyme-Linked Immunosorbent Assay of Aflatoxins B₁, B₂, and G₁ in Corn, Cottonseed, Peanuts, Peanut Butter, and Poultry Feed

Abstract

The development of enzyme-linked immunosorbent assays (ELISA) as screening methods for aflatoxins has progressed swiftly. In the past the sensitive immunoassays required long incubation periods and sophisticated calibration and instrumentation (Chu et al., 1987; Mortimer et al., 1987; Singh and Jang, 1987; Dixon-Holland et al., 1988; Park et al., 1988; Park et al., [in press]). These conditions restricted the use of such assays to scientific laboratories. Recently the use of polyclonal antibodies on membranes in solid phase immunoassay has permitted the non-scientist to obtain rapid and sensitive qualitative results for aflatoxin in grains and grain products (Personal communication, B. Johnson, Environmental Diagnostics, Inc., 2990 Anthony Rd., Burlington, NC 27215; Unpublished data, D. K. Morris, International Diagnostic Systems Corp., P.O. Box 799, St. Joseph, MI 49085). We report here the evaluation of one of these test systems that is capable of detecting aflatoxins B₁, B₂, and G₁ in corn, peanuts, peanut butter, cottonseed, and poultry feed. In this system antibodies are covalently attached to a membrane. The membrane is contained in a cup-like device. Attached to the membrane is a porous absorbent pad that controls the flow of test solution and reagents through the membrane. As the analytes (aflatoxins) flow through the pores, they are immediately captured by the antibodies. Thus the diffusion distances between the analyte and the immobilized antibodies are eliminated and high rates of binding are achieved.